Various types of interdental cleaners or toothpicks have been used since long ago. Toothpicks of plastic materials are widely used nowadays, and an early example of an interdental toothpick is disclosed in JP-1979-170098U. In one embodiment described therein, the toothpick has a stick-like body of hard synthetic resin which is partially coated by a soft synthetic resin. The soft material portion of the toothpick serves to remove dental plaque and the like from the teeth.
Another example of the same basic structure is shown in U.S. Pat. No. 6,158,444 (corresponding to WO 98/16169), where a rod-like carrier made of hard plastics is partially coated by a soft thermoplastic elastomer (TPE).
Further interdental cleaners of similar type are disclosed in EP-A-153,011 and U.S. Pat. No. 3,775,848 and some recent designs are shown in WO-A-2009/150964, WO-A-2012/156025, WO-A-2013/176297, WO-A-2014/005659, WO-A-2014/023395, WO-A-2014/023424, CN-U-201790907, JP-A-2013188299, JP-A-2013192866 and US-A-2014/0008837.
Certain of the interdental cleaners or toothpicks described in these publications are available on the market, and many of them suffer from different drawbacks which users have experienced. Some toothpicks are of too weak structure which means that they break in use. Other interdental cleaners have inefficient brush portions leading to incomplete cleaning of the teeth. Furthermore, certain toothpicks are uncomfortable to grip and may slip. In summary, many prior-art interdental cleaners are hard to handle by users.
From the above it is understood that there is room for improvements.